Certain disease states require treatment using one or more different medicaments. Some drug compounds need to be delivered in a specific relationship with each other in order to deliver the optimum therapeutic dose. One aspect of the present invention is of particular benefit where combination therapy is desirable, but not possible in a single formulation for reasons such as, but not limited to, stability, compromised therapeutic performance and toxicology.
For example, in some cases it might be beneficial to treat a diabetic with a long acting insulin and with a glucagon-like peptide-1 (GLP-1), which is derived from the transcription product of the proglucagon gene. GLP-1 is found in the body and is secreted by the intestinal L cell as a gut hormone. GLP-1 possesses several physiological properties that make it (and its analogs) a subject of intensive investigation as a potential treatment of diabetes mellitus.
There are a number of potential problems that can arise when delivering two medicaments or active agents simultaneously. The two active agents may interact with each other during the long-term, shelf life storage of the formulation. Therefore, it is advantageous to store the active components separately and only combine them at the point of delivery, e.g. injection, needle-less injection, pumps, or inhalation. However, the process for combining the two agents needs to be simple and convenient for the user to perform reliably, repeatedly, and safely.
A further problem is that the quantities and/or proportions of each active agent making up the combination therapy may need to be varied for each user or at different stages of their therapy. For example one or more active agents may require a titration period to gradually introduce a patient up to a “maintenance” dose. A further example would be if one active agent requires a non-adjustable fixed dose while the other is varied in response to a patient's symptoms or physical condition. This problem means that pre-mixed formulations of multiple active agents may not be suitable as these pre-mixed formulations would have a fixed ratio of the active components, which could not be varied by the healthcare professional or user.
Another potential problem may stem from the fact that an increasing number of drug delivery devices, such as pen type drug delivery devices, are being marketed, including ones that are used for the delivery of different types of drugs. The issue of device and/or drug differentiation is becoming of increased importance as there can arise certain safety issues (some life-threatening) associated with a patient or user mistaking one drug delivery device for another device and then administering an incorrect or wrong drug. While device/drug differentiation can be achieved in a number of ways, a preferable method of differentiation is mechanical prevention (i.e., making it difficult or nearly impossible for a device/drug mix up to occur). As just one example, a number of commercially available pen type drug delivery devices are supplied with a dispense interface coupling mechanism that is non-proprietary. That is, with such a dispense interface, the coupling mechanism accommodates the attachment of a conventional Type A needle assembly via a helical thread. For such ‘mono-product’ devices, the use of different Type A needle assemblies is acceptable, as the needle assembly in this instance is simply the means of administering the medicament from the primary reservoir of the drug delivery device.
This may not be the case for Applicants' presently disclosed needle module and systems, where inadvertent use of a needle module with a non-approved primary delivery device could have serious consequences (e.g., such consequences could include unknown health risks as the two formulations may not have been subject to any clinical evaluation or perhaps lacks regulatory approval). Equally, the use of a standard Type A needle with the approved primary drug delivery device may not be desirable in a delivery device system comprising a medicated module, as a patient would not receive the targeted combination dose. In one situation, this might result in reduced therapeutic efficacy. However, in a worse situation, use of a standard Type A needle with the approved primary drug delivery device could result in non-desirable side effects (e.g., in the instance where the secondary medicament had some kind of balancing, cancelling or delaying effect on the pharmaco-kinetics (“PK”) and/or pharmaco-dynamics (“PD”) of the primary medicament contained within the drug delivery device). There are therefore certain safety and clinical benefits to configuring a combination delivery device so as to prevent attachment of a needle module to an incorrect primary drug delivery device. There are also, therefore, certain benefits (e.g., regarding safety and clinical benefits) to configure a combination delivery device so as to prevent attachment of a standard or conventional Type A needle to the combination therapy's primary drug delivery device.
Additional problems can arise where a multi-drug compound therapy is required, because many users cannot cope with having to use more than one drug delivery system or make the necessary accurate calculation of the required dose combination. This is especially true for users with dexterity or computational difficulties. In some circumstances it is also necessary to perform a priming procedure of the device and/or needle cannulae before dispensing the medicaments. Likewise, in some situations, it may be necessary to bypass one drug compound and to dispense only a single medicament from a separate reservoir.
Other problems can arise where a user is called upon to dispense a dose of medicament by way of a delivery device having a manually operated dose administration button. With such a button, the user is called upon to manually push or act upon the button to administer a dose while the dispense interface remains inserted at the injection site. This might cause problems for certain frail users or users with poor dexterity, especially those who might be required to hold down the dose injection button for a certain period of time (e.g., 10 seconds or so) to make sure that the selected dose has been properly administered. Other problems could also arise where the dispense interface is inserted into an injection site at an incorrect insertion depth and dose administration occurs at an incorrect depth.